Thermostatically governed electric laundry iron



G. BRowNlNG 1,908,401

THERMOSTATICALLY GOVERNED ELECTRIC LAUNDRY IRON May 9, 1933.

Original Filed June 17. 1929 3 Sheets-Sheet l ,Z/e 72 ZLoZ/f efozma/y. Mm @zzz g5 G. BROWNING May 9, 1933.

WYERMOSTATICALLY GOVERNED ELECTRIC LAUNDRY IRON Original Filed June 17,1929 3 Sheets-Sheet 2 j ff May 9, 1933.

THERMosTATIcALLY GovERNED ELECTRIC LAUNDRY IRON G. BRowNlNG 1,908,401

5 Sheets-Sheet 3 Original Filed June 1'7, 1929 Patented May 9, 1933UNITED sTATEs,

PATENT OFFICE GEORGE BROWNING, OF WILMETTE, ILLINOIS, ASSIGNOB TOCHICAGO FLEXIBLE SHAFI' COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OFILLINOIS i TBEBHOSTATICALLY GOVERNED ELECTRIC LAUNDRY IRON Original`application med June 1 7, 1929, Serial No. 871,356. Divided and thisapplication iiled April 5,

1900. Serial This ap lication is a division of my application erial No.371,356, filed June 17, 1929, now Patent No. 1,779,960, issued Oct.28,1930.

The purpose of this invention is to provide an improved construction ofan electric laundry iron having thermostatic devices for automaticallygoverning the temperature of the iron by automatically interrupting thecircuit by which it is energized when any predetermined temperature isobtained, and automatically restoring the circuit connection when thetemperature falls below such predetermined degree, with manuallyaccessible and operable means for adjusting the thermostatic devices tovary at will a predetermined degree of temperature at which the circuitis interrupted and restored. It consists in the elements and features ofcon struction shown and described as indicated in the claims.

In the drawings Figure 1 is a top plan view of an electric laundry ironembodying this invention, lwith the hand piece of the handle memberremoved.

Figure 2 is a section at the line 2-2 on Figure 1.

Figure 3 is a fragmentary view consisting of a part of Figure 2 showingthe parts of a thermostatic regulating device in diierent position fromthat shown in Figure 2.

Figure 4 is a plan viewwith the handle and cover or enclosing shell andthe heat storing member removed, and the upper sheath of the heatingunit partly broken away to show the heating coils. l

Figure 5 is a plan view with the handle and enclosing shell removed, andthe heat storing member partly broken away to show the heating unitbelow it.

Figure 6 is a section at the line 6-6 on Figure 2, with the handleupright partly broken away to reduce the view. v

Figure 7 is a section at the line 7--7 on Figure 2. l

, Figure 8 is a bottom plan view of the handle and certain adjustableparts carried on the handle strap.

Figure 9 1s a perspective view of a frame which is mounted on the soleplate for varylng .the thermostatic governing device.

Figure 10 is a section at the plane indicated by the line 10--10 onFigure 9 on an enlarged scale.

Figure 11 is a section at the line 11-11' on Figure 5, on an enlargedscale.

Referring to the drawings: -A isthe sole plate,-the bottom member of thebody of the iron having the working face. D is the heating unit mounteduponlthe upper side of tl sole plate. C is a heat storage member mountedabove the heating unit and serving to hold the latter tightly upon theupper surface ofk the sole plate. J is a cover or enclosing shellhereinafter referred toas the cover shell. E is the handle comprisin .ahand piece, E1, and a handle strap, E2, at the upper end of which thehand piece is carried. A socket for holding a plug not shown) carryingthe, circuit wires not shown) leading to and from the source of current(not shown), is seen at F. F1 and F2 are the plug-en aging circuitterminal pins; f1 and f2 are exible metal strips constituting initialarts of the circuit connections from the pins, F1 and F2, respectively,

'to the heating coils, D1, in the heating unit, D,

laterally .than the latter. For mounting the thermostatic regulatingdevices in the recesses, a and c, there is provided a frame, G, mountedupon the sole plate, overhanging the recess, a, of the latterandextending up into the recess, e, of the storage member. This frame, G,comprises upright lateral webs, 10 extending uninterruptedly over theentire length of the frame, and connected at their upper edges bytransverse webs, 11, 11,

aving uprights, e2,

each extending for a short portion only of the length ofr` the frame,leaving between them suitably extended openings for connections,hereinafter described. which are provided for adjusting thc thermostaticlegulating devices. The frame G, is mounted on the sole plate by meansof laterally projecting lugs. 12` 12, provided at the lower edges of theupright webs. 10` 10, the sole plate having in its upper surfacerecesses, 12, in which the lugs 12. are seated, and at which they aresecured to the sole plate by screws, 13, 13, screwed through said lugsinto the sole plate. This` frame. G, is conveniently arranged forcarrying the plug socket, F, as may be understood from Figure 2.

The thermostatic devices for controlling the operation for maintainingthe iron at predetermined temperature will now be described.

These devices comprise a bi-metallic bar, H. hereinafter referred to asa thermostat, said thermostat being rigidly, but adjustably, secured atone end insulatedly to the sole plate by means of a mountingV fittingconsisting of a U-shaped stamping, 17, having parallel limbs, 17, 17",extending inside the upright side webs, 10. 10, of the frame, G, andpivoted thereto as seen at 17 b, said fitting having an arm, 17,extended from the cross web of its U-form, said arm at a short distancefrom said cross web being bent first upwardly and then to the right, asseen in Figure 2, and having its extremity secured to the sole plate bybeing fastened by a screw, 17d to the top of a post, 17, which isscrewed into the sole plate and adapted to be adjusted vertically byscrewing it more or less into the sole plate, for which purpose it has ahexagonal head, 17. The thermostat, H, is secured insulatedly to thefitting, 17, by bolts, 19, 19 which also secure insulatedly to thefitting and conductively to the thermostat a conductive bracket, 20,which is provided for connecting the thermostat conductively with theheating coil, said connection being effected by the fiexible conductor,f, above mentioned, leading from the coil and secured to the bracket 20,by a binding screw, as seen at 21.

The thermostat, H, is insulated from the U-shaped fitting, 17, by meansof a mica strip. 25, interposed between said fitting and the thermostat,as seen in Fi re 11. The bracket, 20 is insulated from the fitting, 17.by a mica strip, 24, as seen in Figure 11, and the cross web of theU-form of the fitting, 17 has the apertures through which the bolts, 19,19 extend enlarged for ample clearance around the bolts, so that thelatter do not effect electrical conduction from the bracket, 20, to saidfitting, 17.

And the bolts, 19, having their heads binding the under side of thethermostat and their nuts, 19, clamping a washer plate, 26,

onto the upper side of the horizontal arm of the bracket, 20, constituteefective conductors for the current from the bracket, 20, to thethermostat.

The mica strip. 24, is extended along the entire length of thethermostat, and the thermostat carries at its free end a contact button,30, at the end of a spring arm, 31; made fast at the other end to thefree end of the thermostat. The purpose of this spring mounting for thecontact button will be hereinafter explained.

For cooperating with the thermostat in the regulation of the temperatureof the iron, there is provided a cooperating contact carrier, 40,ivotally mounted at one end in the frame, on the pivot pin, 17 saidcontact being carried at the end of a conducting strip, 42, mountedinsulatedly on the contact carrier, said insulation being effected by amica strip, 48, interposed between the contact carrier, 40, and theconducting strip, 42, the conducting strip being secured to the contactcarrier by rivets, 44, 44, insulated from the carrier, as indicated byinsulations consisting of mica washers, 45, interposed under the rivetheads, as seen in Fi res 2 and 3. The conducting strip, 42, whichcarries the contact, 42, is connected in circuit with the heating coilby means of .a flexible conductor shown at f, which is clamped at oneend between the insulating mica strip, 43, and the conducting strip, 42,and connected at the other end to circuit terminal pin, F2, as seen inFigure 7.

For holding the co-operating contact carrier, 40, in definite position,and for adjusting it to vary the temperature limit at which the circuitis interrupted, there is provided a bell crank lever, 50, fulcrumed atits angle on a fulcrum pin, 49, mounted in op ositely positioned lugs,53, 53, projecting up rom the upper edges of the webs, 10, 10, of theframe, G, said lever having a relatively short arm, 51, extendingbetween the webs, 10, 10, of the frame, G, longitudinally of said frame,reflexed u on itself to form a slot, 51, and er.- gaging 1n said slot isa pin, 55, mounted in upstanding lugs, 56, 56, which are folded up fromthe opposite ed es of the cooperating contact carrier, 40, t eupstanding arm of the bell crank lever being extended up through anaperture, 57, in the heat storage member, C, and arranged at its up rend for actuation by a manually operate device which is mounted upon thehandle strap, E2, and projects down through said strap and through thecover shell, J, for engaging said bell crank lever, as will behereinafter more particularly described.

U on considering the construction as thus far ascribed and 1s shown inthe drawings, it may be understood that at normal atmospherictemperature which may be hereinafter referred to as cold the thermostat,H, is

eonsidrably flexed from straight position, substantially as seen inFigure 2, and is adapted to become straight as seen in Figure 3 whenheated to the predetermined temperature limit at which the circuit is tobe interrupted for preventing further rise in temperature. And it willbe understood that at the position corresponding to cold temperature ofthe iron, and at any position to which the cooperating contact button,30, is intended to be adjusted, the contact button, 42, is at suchposition that the thermostat in its normally iexed form holds thecontact button, 30, in contact with the contact button, 42, with thespringarm, 31,' flexed as seen in Figure 2 and reacting resiliently forstressing the contact button, 80, against the contact button, 42a. Andit will be recognized, therefore, that the two contact buttons willremain in contact, keeping the circuit closed and the heating unitenergized until the thermostat becomes heated to a degree at which itwill be straightened enough to take up the resilient action of thespring stem, 31, of the contact butt-on, 30 and that upon becomingheated beyond this point and further straightened it will withdraw theContact button, 30, from the contact button, 42a, and cause the circuitto be interrupted. And it will be recognized that upon this interruptionand the cooling of the ironk and the. thermostat which will follow uponthe thermostat becoming slightly cooled will again carry the Contactbutton, 30, into contact with the button, 42a, closing the circuitconnection and continuing the heating and maintaining the temperatureofthe irony to the maximum for which the adjustment is made. The resultis that when the iron is in use so as to utilize the heat by radiationor conduction, the circuit will remain closed as long as the utilizedheat substantially equals the heat generated by the heating unit; andthat when the circuit 1s interrupted in the manner described by themomentary rise of the temperature beyond the predetermined degree, ifthe conditions of use are such as to cause continued radiation of theheat, causing the iron to become cooled below the limit, the circuitwill be immediately closed, and if the heat generating capacity of theheating unit is substantially equal to the capacity of the iron forgiving oi heat by conduction or radiation, there will result a rapidsuccession of openings and closii gs of the circuit, with the practicaleiect of a continually closed circuit, with unappreciable variation ofthe temperature, causing the generation of the precise amount of heatutilized by loss of radiation from the iron.

Figure 3 sh ws the contacts, 30 and 42, and the thermostat atsubstantially straight position which may be understood to be thepositionand form of the thermostat at the maximum temperature. Thisfigure may be understood as intended to show the adjusting devices setfor holding the cooperating contact carrier atposition for mediumtemperature. And from this showing it may be understood that the ironhas been operating at high temperature and the operator has adjusted theadjusting devicesv to the low or lower temperature, as medium, therebycausing thecontacts to be Separated; and that they will remain thusseparated until the thermostat cools down approximately to thetemperature for which the adjustment is made, this cooling causing thethermostat to become flexed for carrying the contact button, 30, up intoContact again with the contact but-ton, 42a, causing the circuit to beclosed and the heating unit energized for maintaining that temperature.

It ma;7 be understood from the foregoing description that for theordinary purposes of a laundry iron the adjusting devices will bearranged so that at the adjustment for the lowest temperature at whichthel iron is to be operated the circuit will be closed-that is, thebuttons will be in contact-when the iron is cold, so that when the ironis connected by the plug in the usual manner with the source of current,it will begin to warm up immediately, which could not happen unless thecircuit in the iron itself were closed. And in order that the circuitshall not be immediately opened by change of form of the thermostat, thespring stem, 3l, of the contact, 30, at the cold condition must bereacting resiliently for stressing the contact, 30, against the contact,42a, to an extent requiring the straightening of the thermostat enoughto offset and compensate that resilient reaction, by rise of temperatureto said lowest temperature limit at which the iron is to be operated;and that the structure may operate in this manner is the purpose of thespring stem, 3l, of the contact, 30.

Upon careful consideration of the structure it may be recognized thatthe principle of operation of the thermostat requires that it should beiixedly held at one end so that the change of form due to change oftemperature shall cause the movement of the free end at which thecontact is carried to be definite and. to correspond always to 'thetemperature change, as could not be depended upon to be the case if theother end could perform part o the movement. And it will be recognizedalso that the temperature at which the contacts will separate depends,to a considerable extent, on the range of the resilient action of thespring stem, 31,01? the contact, 30, and the extent to which it isflexed or straightened from the normal form at the normal position ofthe parts as assembled at normal atmospheric temperature. And it will berecognized that the slight and unavoidable variations in the stiffnessof the spring stem and in its normal form, as being straight or slightlycurved, will make it extremely dif-v cult to ensure uniformity indiil'erent irons even of the same lot, in respect to the temperaturelimit at which the contacts will separate at any given adjustment of thecooperating contact carrier, as at high or low.` It is in view of theseconsiderations that the thermostat is mounted as described, so that itis adjustable at its rigidly secured end by setting the threaded post,17, more or less deeply into the sole plate.

The manually operable ad'ustingzdevices for-l setting the thennostaticevioes to vary the redetermined temperature limit will now be escribed:v v These adjusting devices comprise a slide, 60, on the horizontalportion of the handle strap, said slide being mounted upon the u perside of said handle strap and having c as ing lugs, 61, enga 'ng thelateral ed of the' strap as seen 1n igure 2. This slide has a ran ofmovement on the handle strap between t e posts which secure it to thebody of the iron', as hereinafter more particulary described, and withinthe range of said sli in movement the handle strap has markingsindicating several degrees of temperature'for which .the device may beadjusted, said markings consisting, as seen in Figurel, in the words Hih, Med. indicating medium) and Low and the sli e has a reading slot, 70,through which these markings may be read at the positions respectivelyof the slide corresponding to the temperature indicated. The slidecarries an operating stem, 63, which ismounted in a bearing, 62, formedat the center of an up-struck hollow boss, 62, of

the slide.A Said stem extends down through a .lon 'tudinal slot, 68, inthe handle stra and t rough a correspondingly positione slot, 82, in thecover shell, J, and engages at its lower end the upper end of theupstanding arm of the bell crank, 50, as seen in Figure 2 and heretoforementioned. The operatin stem, 63,-is provided at its upper end witlgx anoperatingk-nob, 64, which is itself journaled on the bearlng, 62, forassisting in holding the operating stem accurately in the verticalposition. The operating stem carries rigid with it under the hollowboss, 62, a disk, 65, having a rigidly projecting pin, 66, which-engagesa short transverse slot, 67, in the handle stra opposite the middlepoint of the length o the slot, 68, in which the operating stem, 63,moves for operating the bell crank lever, 50. Upon considering thisconstruction it will be understood that upon rotating the handle, 64,the pin, 66, becomes a fulcrum about ywhich said disk swings as it islocated by the handle, the pin, 66, moving in the transverse slot adistance corresponding to thel height of the segment de fined by the arcof movement of the pin about the center of its rotative movement, viz.,the operating stem, 62; and that accordingly with only an amount ofmovement of the pin tranaversel of the handle strap equal to the hei htof t at segment, there il obtained longitu inal sliding movement of theslide, 60, equal to the chord of the arc of said se ment, which issuicient for shifting the sli e through the entire range of movementnecessary Y or operating the bell crank lever, 50, to eil'ect themaximum adjustment necessary and to shift the slot, 70, from High to Lewition of the temperature markings on the e'strap.

I claim:

1. An electric laundry iron having in combination with a heating unitand a sole late on which the heating unit is mounte for heating theplate, the sole plate having a recess in its upperside at a portion ofits area which is not occupied by the heating unit; a thermostatic barpositioned lin said means for securin it rigidly at one and with theother end for movement due to changes f'forms of the bar upon chan oftemperature; a circuit-making-and-brea g contact carried by the bar atits free end; a pivoted contact carrier, and a co-o rating contactcarried thereb remotely om the pivot and positioned or meeting the firstmentioned contact yin the pivotal movement of said co-ope ting contactcarrier, one of said contactsbeing resiliently mounted on the part whichcarnes it, and a frame mounted on the sole plate over the recess thereinand extendin up above the level of the upr surface of the sole plate,the thermostatic ar and the co-operat'mg contact carrier be-v inxbothmounted in the manners respectively 1n 'cated on said frame with theco-operating contact carrier above the upper surface of the sole'plateand above the level of the heating unit.

2. An electric laundry iron having in combination withf a heating unitand a sole late on which the heating unit is mounte for `heating theplate, the sole plate having a recess in its upper side at a portion ofits area which is not occupied by the heating unit; a thermostatic barpositioned in said recess, means for securing it rigidly at one end withthe other end free for movement due to changes of forms. of the bar uponchan e of temperature; a circuit-making-and-brea 'ng contact carried bythe bar at its free end; a pivoted contact carrier, and a co-operatingcontact carried thereby remotely from the pivot and positioned formeeting the first mentioned contact in the pivotal movement of saidco-operating contact carrier; a resilient stem by which the firstmentioned contact 1s mounted at the free end of the thermostatic bar,and a frame mounted on the sole plate over the recessV therein andextending up y'above the level of the upper surface of the sole plate,the thermostatlc bar and the co-operating contact carrier being both llllll

mounted in the manners respectively indicated on said frame with theco-operating contact carrier above the upper surface of the sole plateand above the level of the heating unit. l

3. An electric laundry iron having in combination with a heating unitand a sole late on which the heating unit is mounte for heating theplate, a heat storage member lodged above the heating unit, the soleplate having a recess in its upper side and the heat storage memberhaving a recess in its lower side registering with the recess of thesole plate, a frame structure mounted on the sole plate and extendin eatstorage mem r, a thermostatic bar mounted on the frame and positionedthereby in the recess of the sole plate, a contact carried by thethermostatic bar, a co-o erating contact carrier adjustably mounte onthe frame, and a contact carried thereby positioned for co-operatingwith the contact carried by the thermostatic bar, said co-o eratingcontact carrier being carried by the rame substantially entirely in therecess of the heat storage member at normal position of the parts at apredetermined temperature of the thermostatlc bar, connections :forad'usting the co-operating contact carrier exten ing up through the.heat stora e member, an operating handle for the iron and mountingmeans for the same extended up from the said frame through the heatstorage member, and manually accessible and operable means for operatingthe co-operating contact-car rier-adjusting connections mounted on thehandle.

In testimony whereof, I have hereunto set m hand at Chicago, Illinois,this third day o April, 1930.

' GEORGE BROWNING.

into the recess of the

